Booklets of the aforedescribed kind are normally produced in the following way.
A flat sheet of board and/or plastic is folded to provide a cover that comprises two cover sheets and a spine located therebetween. A string of melt glue is applied to the inner surface of the spine, wherein the glue melts when heated and solidifies and adheres to said inner surface as it cools. The cover sheets are then folded towards one another to form a cover with the glue string located between the sheets. The finished covers are then packed and delivered to the user, who removes a cover from the package and inserts a bundle of sheets between the cover sheets with one side edge of the sheets in abutment with the glue string. The user then places the cover and enclosed sheets in a binding apparatus, e.g. of the kind described in SE-B 434 367, so as to bring the outer surface of the spine into contact with a hot plate. The glue melts within a given space of time and the bundle of sheets sinks down into the molten glue. The user then removes the cover and sheet bundle from the apparatus and allows the glue to cool, so as to firmly affix the edges of the sheets to the spine.
The aforedescribed method is both complicated and time-consuming, particularly when a large number of booklets of one and the same kind or of different kinds shall be produced.
U.S. Pat. No. 5,102,277 teaches a method and a machine for binding bundles or sets of sheets in covers of the aforedescribed kind. Although the method and the machine described are developments of the manual binding of sheets achieved with binding apparatus according to SE-B 434 367, the method and machine do not enable bundles of sheets, e.g. dispensed from a copier, to be combined with the empty covers that are introduced into the machine in bundles.
U.S. Pat. No. 2,549,890 teaches a bookbinding machine. Book blocks are provided with glue on their respective side surfaces and introduced into covers that fall down singly from a magazine in the machine. The machine thus produces products of a kind other than booklets, wherein each product consists of a cover that is affixed to a sheet bundle solely at the spine of the cover. Moreover, the machine does not include means for activating a glue string so as to affix the bundle of sheets to the cover spine.
GB-A 1 258 746 teaches a bookbinding machine for producing book blocks by applying melt glue along one edge of the book block. The machine thus produces products of a kind other than booklets which comprise of bundles of sheets affixed to the spines of the booklets. Moreover, this machine does not include sheet-bundle and booklet transporting means.
U.S. Pat. No. 3,093,396 teaches a bookbinding machine in which paper sheets are joined together along one side edge thereof by means of several adhesive layers, such as to form a book block. Each book block is then combined with a cover that lacks a binding agent. The adhesive layers on the book block are then activated via the cover spine, to join the block to the spine. The machine thus produces products of a kind other than booklets that consist of covers having spine-applied glue strings that are interconnected with bundles of sheets which are loose relative to one another prior to binding. Moreover, the covers are not collected in any form of cassette or the like from which they are transported to book blocks in the known machine.
WO 94/26 535 teaches a method and a device which constitutes a step forwards in relation to the aforedescribed techniques, wherewith the manual work is reduced, the production rate is increased, and the quality of the finished booklets improved. This has been achieved with the method and the device according to this publication by virtue of a method that comprises the steps of
moving a sheet bundle to a first position by means of a first power-driven transporter means; PA1 moving by means of a second power-driven transporter means one cover from a plurality of covers that include a glue string and that are placed in the immediate vicinity of one another to a second position in which said one cover is distanced from the remaining covers; PA1 combining the sheet bundle with the glue-string provided cover such as to enclose said bundle in said cover with said side edge of the sheet bundle facing the glue string; and PA1 moving the cover and the enclosed sheet bundle past an activator that functions to activate the glue string so as to bind said side edges of said bundle to the inner surface of the spine. PA1 a first power-driven transporter means for moving a sheet bundle to a first position with the sheets in a mutually non-bound state; PA1 a second power-driven transporter means for moving a cover that includes a glue string to a second position distanced from a plurality of covers that include glue strings and that are placed in the immediate vicinity of one another; PA1 an assembly means for combining the sheet bundle with said cover provided with a glue string; PA1 movable pick-up means for picking up the cover provided with said glue string and said sheet bundle, with the side edges of the sheet bundle in abutment with the glue string; and PA1 activator means for activating the glue string during movement of either the pick-up means or the activator means, so as to bind the side edges of the sheet bundle with the inner surface of the spine.
The device for carrying out the described method comprises
Although the apparatus described in WO 94/26 535 solves many problems related to apparatus of the kind concerned, there is still room for further improvement. In the case of the known apparatus, the covers are placed in an obliquely positioned cassette. As a result of the combined effect of the intrinsic weight of the covers, the spring force exerted by the half-open covers and the uneven bias of these forces, the friction between the covers and between said covers and the cassette makes it difficult to take a cover from the cassette, which is liable to result in disturbances in operation.
Another problem with such apparatus and such a method is associated with the desire to bind booklets of mutually different thicknesses, depending on the number of sheets or leaves in the bundle to be bound. Bundles of different thicknesses require different types of folders which can vary primarily with respect to the thickness of the spine. Thus, a given cover will correspond to a given range of sheet bundle thicknesses. When the wrong cover is used for a given sheet bundle, the result will be unsatisfactory. Consequently, it is desirable to improve the aforesaid binding method in a way which will eliminate this problem.
The object of the present invention is to overcome these problems, i.e. to facilitate collection of a cover from its magazine and to avoid a wrong combination between bundle thickness and the cover used.
This object is achieved in accordance with a first aspect of the invention by a method of the kind defined in the preamble of Claim 1 and having the characteristic features set forth in the characterizing clause of said Claim.
According to a second aspect of the invention, the object has been achieved with apparatus of the kind defined in the preamble of Claim 14 and having the characteristic features set forth in the characterizing clause of said Claim.
According to a third aspect of the invention, the object has been achieved with apparatus of the kind defined in the preamble of Claim 19 and having the characteristic features set forth in the characterizing clause of said Claim.
According to a fourth aspect of the invention, the object is achieved with the aid of an accessory in the form of a cassette of the kind defined in the preamble of Claim 24 and having the characteristic features set forth in the characterizing clause of said Claim.
Because the covers are positioned vertically in the readiness position, the least possible friction will be generated when removing the covers from the magazine, therewith facilitating this stage of the process and avoiding the aforesaid problem in this respect. The risk of using a wrong cover can be eliminated by code-marking the covers or the cassette in which the covers are stored and then comparing the code with the thickness of the sheet bundle concerned.
Preferred embodiments of the inventive method, apparatus and accessory are set forth in respective dependent Claims.
The invention will now be described in more detail with reference to preferred embodiments thereof and also with reference to the accompanying drawings, in which
FIG. 1 is a schematic side view of earlier known apparatus;
FIG. 2 is a sectional view taken on the line II--II in FIG. 1;
FIG. 3 is a side view in larger scale of the apparatus shown in FIGS. 1 and 2;
FIG. 4 is a schematic side view of inventive apparatus;
FIG. 5 is an end view of part of the apparatus shown in FIG. 4; and
FIG. 6 is a block schematic that illustrates a part of one embodiment of the invention.